Image forming device and method of interpolation of missing image dots

Abstract

An image forming device includes: a hardware processor that performs halftone processing on input image data using a threshold matrix of a dither method, and that, when dot missing exists in a formed image by the image forming part, performs interpolation by rearranging a missing dot to peripheral pixel position; and an image forming part that forms an image on a recording medium on the basis of image data after halftone processing by the halftone processing part, wherein the hardware processor, using the threshold matrix, sets a blank pixel having a high probability of being generated next when gradation is increased, as a rearrangement destination of the missing dot.

What is claimed is: 
     
       1. An image forming device comprising:
 a hardware processor that performs halftone processing on input image data using a threshold matrix of a dither method, and that, when dot missing exists in a formed image by an image forming part of the image forming device, performs interpolation by rearranging a missing dot to peripheral pixel position; and 
 the image forming part that forms an image on a recording medium on the basis of image data after halftone processing by a halftone processing part of the hardware processor, wherein 
 the hardware processor is configured to set, as a rearrangement destination of the missing dot, a pixel of a threshold closest to a threshold for which an image is formed among pixels of thresholds for which images are not formed. 
 
     
     
       2. The image forming device according to  claim 1 , wherein
 the image forming part causes a plurality of nozzles to discharge droplets of ink and land the droplets on the recording medium to form an image. 
 
     
     
       3. The image forming device according to  claim 2 , wherein
 the missing dot is generated due to a defective nozzle that cannot discharge the droplets of ink and a defective nozzle of which a landing position of the droplets of ink on the recording medium deviates. 
 
     
     
       4. The image forming device according to  claim 2 , wherein
 the ink is UV curable ink or phase change ink. 
 
     
     
       5. The image forming device according to  claim 3 , wherein
 the hardware processor acquires information on the defective nozzle, and 
 the hardware processor performs interpolation processing of the missing dot on the basis of information acquired by the hardware processor. 
 
     
     
       6. The image forming device according to  claim 1 , wherein
 the hardware processor, in a dot of a pixel row of a pixel of interest and a peripheral pixel row, switches the rearrangement destination of the missing dot in accordance with each state of dot missing in successive two pixels, dot missing in two pixels with one pixel skipped therebetween, and dot missing in one pixel. 
 
     
     
       7. The image forming device according to  claim 6 , wherein
 in a dot missing state in successive two pixels, the hardware processor sets a pixel in an adjacent pixel row on a side in which dot missing is not generated, out of two adjacent pixel rows both adjacent to the a pixel row of the pixel of interest, as the rearrangement destination of the missing dot. 
 
     
     
       8. The image forming device according to  claim 6 , wherein
 in a dot missing state in two pixels with one pixel skipped therebetween, the hardware processor shares a pixel in a pixel row between pixel rows of the two pixels as the rearrangement destination of the missing dot of the two pixel rows. 
 
     
     
       9. The image forming device according to  claim 6 , wherein
 in a dot missing state in one pixel, the hardware processor sets each pixel in two adjacent pixel rows both adjacent to the pixel row of the pixel of interest as the rearrangement destination of the missing dot. 
 
     
     
       10. An image processing device comprising:
 a hardware processor that performs halftone processing on input image data using a threshold matrix of a dither method, and that, when dot missing exists in an image formed on a recording medium on the basis of image data after halftone processing by the hardware processor, performs interpolation by rearranging the missing dot in a peripheral pixel position, wherein 
 the hardware processor is configured to set, as a rearrangement destination of the missing dot, a pixel of a threshold closest to a threshold for which an image is formed among pixels of thresholds for which images are not formed. 
 
     
     
       11. An image processing method comprising:
 performing halftone processing on input image data using a threshold matrix of a dither method; and when dot missing exists in an image formed on a recording medium on the basis of image data after halftone processing, performing interpolation by rearranging the missing dot in a peripheral pixel position, wherein 
 setting, as a rearrangement destination of the missing dot, using the threshold matrix, a blank pixel in an adjacent pixel row to the missing dot a pixel of a threshold closest to a threshold for which an image is formed among pixels of thresholds for which images are not formed.